1. Field of the Invention
This invention relates generally to a motorized track system, and more particularly toward a transmission for a motorized track system of the type used in position adjustors for vehicular seats, windows and the like.
2. Related Art
Vehicle seat assemblies are often provided with a motorized track system that enable the position of the seat assembly within a motor vehicle to be adjusted in the forward and rearward directions. Similarly, vehicular window assemblies may include a motorized track system of similar construction to enable the position of the window to be adjusted in up and down directions. In each case, the supported element is guided by the motorized track system for back and forth movement to change its position, as desired.
In the case of vehicular seat assemblies, for example, such adjustment capability is desired to enable vehicle operators of various body dimensions to be seated comfortably within the motor vehicle. In these systems, an electric motor may be coupled to a lead screw positioned within a sliding track assembly. In such an arrangement, the lead screw may be fixed or may rotate but a drive nut interacts with the lead screw through motor-driven rotation to move the vehicle seat assembly forward or rearward. A motorized window regulator assembly may work in much the same manner.
A transmission is generally provided in these types of motorized track systems for transferring power from the motor to the drive nut. In configurations where a pair of sliding tracks are employed, the electric motor may be mounted on a transverse beam bridging each of the tracks, for example in the center of the tracks or at one end of the tracks. Because certain components within the transmission rotate while others are held generally stationary, vibrations may be produced within the transmission when the transmission is operational, thereby causing noise. Another cause of noise is lateral movement of the components within the transmission housing.
Various proposals have been advanced for addressing the noise issues in a transmission for a motorized track system. For example, U.S. Pat. No. 7,051,986 to Taubmann et. al., granted May 30, 2006, discloses a system wherein a shim disk, identified as item number 96′, is used to compensate for axial play. Shim disks are subject to manufacturing variances, however and may not consistently address the noise issues. Accordingly, there is a need for a motorized track system for use in vehicular applications that meets or exceeds the established strength, speed and noise requirements. There is also a need to provide a reliable transmission that includes shock absorbing components to reduce the vibration between those components in the transmission, and to reduce noise and to eliminate lateral movement of certain components. There is a further need to provide a reliable, acceptable motorized track system for providing translational adjustment, which avoids one or more of the above-noted problems.